As well, all trees in the immediate vicinity of the fence are to be cleared if SCP-XXXX escapes by climbing up one of the trees.

Eh, you should have a response for more than one potential breach.
Additionally, the SCP could be long gone before the forest is cleared.
This may be The Foundation, but nevertheless things like clearing a forest take time.

encircling the 120 acres of forest achieves its containment.

If this achieves containment, the procedures would end here.

From an interview with an elder of the ██████ ██████ Indian Tribe that lived near Salem, legend has it that a small number of this tribe began to experience hallucinations during the same period as the hysteria in Salem.

This doesn't look like a qualify-able interview for a scientific article.
"legend has it." That's my main complaint.

SCP-XXXX is a humanoid entity of indeterminate race and sex, standing about 1.8 meters and weighing approximately 60kg. SCP-XXXX wears a black, face-concealing cloak. The anomaly is capable of speech. SCP-XXXX has a flute within its cloak. This was discovered by high-resolution satellite imaging on █/ █/20██. SCP-XXXX plays its flute about twice a week. SCP-XXXX itself is harmless but its anomalous effects can cause minor or major issues.

This sounds like a video game main character.
Also, it seems unclear if anyone has actually come into contact with the SCP.
If not, how would you know the weight?

It passively generates hallucinations

What are "passive hallucinations?"
Is this a real term?

It was noted that they fell under the influence of SCP-XXXX’s flute. A wild wolf acquired by Foundation personnel was kept caged at the forest periphery and observed. The wolf became very agitated. The wolf violently tried to escape the cage, injuring itself.

How can you note this?
You don't know this information.
The wolf may have been exhibiting normal behavior…

Finally, I'd advise for you to bold the names in the interview when you're specifying who is speaking. Not a necessity, but it would help the flow of the read since you start a lot of action-descriptions with the D-operatives name.

SCP-XXXX is currently in its forest in eastern Massachusetts with Area-48 constructed around the periphery of its forest.

Describing the area as "its forest" is kind of awkward.

A chain link fence should topped with Cortina wire encircling the 120 acres of forest achieves its containment.

"should be topped", I think you mean "concertina wire", your sentence doesn't make sense since you move into the containment of the object from the description of the fence with no transition, and "achieves its containment is awkward phrasing.

Electromagnetic jammers are to impede hallucinations and flute music generated by SCP-XXXX is employed as part of the barrier

This sentence has the same "what the hell is it referring to" problem as the one above.

As well, all trees in the immediate vicinity of the fence are to be cleared if SCP-XXXX escapes by climbing up one of the trees. In the estimation of the Foundation it is not possible for SCP-XXXX to breach this containment;

You don't open a sentence with "as well." And what sense does this make? "Well it escaped, better cut the trees down"? How about cutting down the trees as a way to prevent its escape? You should also term it "breach containment" rather than "breach this containment."

History:

You're burying the lede as well as mangling the format for no real reason. Tell us what it is (i.e. "the description") before you get into the background.

much information was obtained from local ledgers

"Ledger" is a specific thing, it's a collection of financial and/or accounting data. I don't think that's what you mean.

and from Indian legend obtained by interview

Researchers would be a little more specific than referring to information resources derived from local Native American tribes as "Indian legend".

SCP-XXXX lived with a black smith and his daughter, Richard ███████ and Melody ███████

It's "blacksmith".

The well-documented issues of witchcraft mania and hangings in Salem began shortly thereafter.

Informal tone. "Well-documented" is a subjective term, as well as "mania" in this context.

legend has it

No place in a clinical document for this.

As well, some of their domesticated horses reverted to a feral state.

Again with the "as well". Stop doing that.

Legend states that these Indians drove this “demonic” anomaly deep into a forest and only then did Salem end its witch-hunts and hangings.

There are actual historic reasons for this that make a lot more sense than "some Indians chased a monster back into the forest."

The Foundation was alerted to the possibility of a dangerous presence when a Native American Agent ████

The Foundation has a special "Native American Agent" title?

alerted Dr. Smith this ancient forest demon had been “awakened”.

This is both unnecessary fluff lengthening the article and very colloquial and informal.

The agent walked his dog of 8 years through this forest and was violently attacked by his formerly loving pet.

"Formerly loving" is poor tone.

SCP-XXXX has a flute within its cloak. This was discovered by high-resolution satellite imaging on █/ █/20██.

Specifying the date for something like this is informational overkill. Also, really? They used a spy satellite to take a picture like that? Wouldn't it make more sense to just have someone with a decent telescopic lens take a photo like that?

Anomalous effects may become manifest

"may manifest", not "may become manifest"

It passively generates hallucinations that can make the individual experiencing them appear unhinged.

"unhinged" is a subjective and therefore useless descriptor in this context.

losing its domestication

This is kind of an odd description.

It will revert to a feral state and become instances of SCP-XXXX-1.

"become an instance"

Doctor, I swear to God that noose is right there! But, I’ll just keep going…

This is cringe-worthy dialogue, mostly because it exists solely to move plot and doesn't sound anything like something a person would actually say. This is emblematic of the dialogue throughout.

So, this is riddled throughout with grammatical and tonal errors. You've got the description buried deep in the article, which is poor writing for this format. The description should present a clear idea of the item in question in an immediate manner, and the description should come before the background info.

The central concept is fundamentally uninteresting. It's essentially "thing what makes you crazy", which we have seen hundreds of times now. This doesn't really add anything new to that trope. The fact that it was responsible for the Salem Witch Trials is especially silly. That historical phenomenon happened for a variety of reasons, all of which are more plausible (and frankly a lot more interesting) than "scary monster in the forest crazied us all into it".

With a weak starting concept like this one, the rest of the material comes across as article filler, generating length but no real interest. The "history" section is extremely silly. Foundation agents finding anomalies while walking their dogs or whatever is a relic of older articles, which would frequently feature an agent finding some cursed item or whatever at a yard sale without considering how astronomically unlikely something like that would be.

The sound sample is also fairly unnecessary, and comes across as a gimmick. The exploration log, as stated above in the line-by-line, is full of unrealistic dialogue, and deepens the sense that this is trying way too hard to be spooky, complete with the mysterious masked figure.

This article isn't really one I would find salvageable in any form. I would work more on a fundamental grasp of English and writing in general, and get a sense of what kind of writing is successful around here by reading more of the wiki.

I don't think people are allowed to edit your sandbox directly, but I have seen line-by-line comments with directions for fixing grammar issues.

I personally would put this on hold, as humanoids are a bit difficult to pull off. Just remember "Safe Class" is not simpler, and are not always easier to write.
Though if you plan to convert into another idea, wait for it to come. Until then you can try your hand at polishing this yourself. I wouldn't scrap this though.

Final Note: You still need grammar. Even if you have the easiest idea ever, grammar is always a must.

This is cringe-worthy dialogue, mostly because it exists solely to move plot and doesn't sound anything like something a person would actually say. This is emblematic of the dialogue throughout.

Although I agree this exists solely to move the plot, it sounds exactly like what this particular D-Class personnel would say. Given previous dialog , he obviously wants Foundation personnel to like him, and fears termination. He know knows that not co-operating may put him into that line, so his fear if the foundation overrides his fear of the noose. That "but," is his consideration.

My opinion anyways. Everything else that was stated seemed like awesome critique, and I still think the sentence needs to be rewritten.
The article definitely needs to be rewritten.

Don't really think this document needs to be written per se…but it does need to written better with better wording. But I see your point about starting small with a Safe Class SCP. I do have an SCP that is a safe class, but I wrote it a LOOOONG time ago this year and needs to be re-written. Once I re-write it, I'll start another thread for people to help me with it because it REALLY needs help with critiquing. (This is to Professor Will)

A humanoid that makes people crazy, and has appeared in history is, frankly, an extremely difficult write-up.

There are a ton of Safe SCPs that are also hard to write, especially since there are already a ton of them written.

If you want any personal help, you can look at my sandbox, first tab to see my opinions and optional helpstuffs when it comes to discussing other's work before, or after forums get exhausted. (You can skip the "&" collapsible)

You also don't have to take the offer. If you wanna solo this until your next thread sometimes that's the best thing to do. Especially since I'm not exactly a "veteran" as this Forum describes many of the high-class editors here.

Also, when I highlighted definitely I didn't mean per se. I meant this wouldn't work at all if you put it up as a final. It's not there yet.